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esp-idf/components/mdns/mdns.c

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Initial mDNS component and example
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// Copyright 2015-2016 Espressif Systems (Shanghai) PTE LTD
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "mdns.h"
#include <string.h>
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#ifndef MDNS_TEST_MODE
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#include "sdkconfig.h"
#include "freertos/FreeRTOS.h"
#include "freertos/queue.h"
#include "freertos/semphr.h"
#include "lwip/ip_addr.h"
#include "lwip/pbuf.h"
#include "lwip/igmp.h"
#include "lwip/udp.h"
#include "esp_wifi.h"
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#endif
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#define MDNS_FLAGS_AUTHORITATIVE 0x8400
#define MDNS_NAME_REF 0xC000
#define MDNS_TYPE_AAAA 0x001C
#define MDNS_TYPE_A 0x0001
#define MDNS_TYPE_PTR 0x000C
#define MDNS_TYPE_SRV 0x0021
#define MDNS_TYPE_TXT 0x0010
#define MDNS_TYPE_NSEC 0x002F
#define MDNS_TYPE_ANY 0x00FF
#define MDNS_CLASS_IN 0x0001
#define MDNS_CLASS_IN_FLUSH_CACHE 0x8001
#define MDNS_ANSWER_ALL 0x3F
#define MDNS_ANSWER_PTR 0x08
#define MDNS_ANSWER_TXT 0x04
#define MDNS_ANSWER_SRV 0x02
#define MDNS_ANSWER_A 0x01
#define MDNS_ANSWER_AAAA 0x10
#define MDNS_ANSWER_NSEC 0x20
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#define MDNS_ANSWER_SDPTR 0x80
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#define MDNS_SERVICE_PORT 5353 // UDP port that the server runs on
#define MDNS_SERVICE_STACK_DEPTH 4096 // Stack size for the service thread
#define MDNS_PACKET_QUEUE_LEN 16 // Maximum packets that can be queued for parsing
#define MDNS_TXT_MAX_LEN 1024 // Maximum string length of text data in TXT record
#define MDNS_NAME_MAX_LEN 64 // Maximum string length of hostname, instance, service and proto
#define MDNS_NAME_BUF_LEN (MDNS_NAME_MAX_LEN+1) // Maximum char buffer size to hold hostname, instance, service or proto
#define MDNS_MAX_PACKET_SIZE 1460 // Maximum size of mDNS outgoing packet
#define MDNS_ANSWER_PTR_TTL 4500
#define MDNS_ANSWER_TXT_TTL 4500
#define MDNS_ANSWER_SRV_TTL 120
#define MDNS_ANSWER_A_TTL 120
#define MDNS_ANSWER_AAAA_TTL 120
#define MDNS_HEAD_LEN 12
#define MDNS_HEAD_ID_OFFSET 0
#define MDNS_HEAD_FLAGS_OFFSET 2
#define MDNS_HEAD_QUESTIONS_OFFSET 4
#define MDNS_HEAD_ANSWERS_OFFSET 6
#define MDNS_HEAD_SERVERS_OFFSET 8
#define MDNS_HEAD_ADDITIONAL_OFFSET 10
#define MDNS_TYPE_OFFSET 0
#define MDNS_CLASS_OFFSET 2
#define MDNS_TTL_OFFSET 4
#define MDNS_LEN_OFFSET 8
#define MDNS_DATA_OFFSET 10
#define MDNS_SRV_PRIORITY_OFFSET 0
#define MDNS_SRV_WEIGHT_OFFSET 2
#define MDNS_SRV_PORT_OFFSET 4
#define MDNS_SRV_FQDN_OFFSET 6
typedef struct {
char host[MDNS_NAME_BUF_LEN];
char service[MDNS_NAME_BUF_LEN];
char proto[MDNS_NAME_BUF_LEN];
char domain[MDNS_NAME_BUF_LEN];
uint8_t parts;
uint8_t sub;
} mdns_name_t;
typedef struct {
char host[MDNS_NAME_BUF_LEN];
char instance[MDNS_NAME_BUF_LEN];
char txt[MDNS_TXT_MAX_LEN];
uint16_t priority;
uint16_t weight;
uint16_t port;
uint32_t addr;
uint8_t addrv6[16];
uint8_t ptr;
} mdns_result_temp_t;
typedef struct {
const char * host;
const char * sub;
const char * service;
const char * proto;
const char * domain;
uint8_t parts;
uint8_t done;
} mdns_string_t;
typedef struct mdns_service_s {
const char * instance;
const char * service;
const char * proto;
uint16_t priority;
uint16_t weight;
uint16_t port;
uint8_t txt_num_items;
const char ** txt;
} mdns_service_t;
typedef struct mdns_srv_item_s {
mdns_service_t * service;
struct mdns_srv_item_s * next;
} mdns_srv_item_t;
typedef struct mdns_answer_item_s {
mdns_service_t * service;
uint8_t answer;
struct mdns_answer_item_s * next;
} mdns_answer_item_t;
struct mdns_server_s {
tcpip_adapter_if_t tcpip_if;
struct udp_pcb * pcb;
const char * hostname;
const char * instance;
mdns_srv_item_t * services;
xSemaphoreHandle lock;
xQueueHandle queue;
struct {
char host[MDNS_NAME_BUF_LEN];
char service[MDNS_NAME_BUF_LEN];
char proto[MDNS_NAME_BUF_LEN];
bool running;
xSemaphoreHandle lock;
mdns_result_t * results;
} search;
};
#define MDNS_MUTEX_LOCK() xSemaphoreTake(server->lock, portMAX_DELAY)
#define MDNS_MUTEX_UNLOCK() xSemaphoreGive(server->lock)
#define MDNS_SEARCH_LOCK() xSemaphoreTake(server->search.lock, portMAX_DELAY)
#define MDNS_SEARCH_UNLOCK() xSemaphoreGive(server->search.lock)
static const char * MDNS_DEFAULT_DOMAIN = "local";
static const char * MDNS_SUB_STR = "_sub";
static mdns_server_t * _mdns_servers[TCPIP_ADAPTER_IF_MAX] = {0,0,0};
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#ifndef MDNS_TEST_MODE
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static TaskHandle_t _mdns_service_task_handle = NULL;
static QueueSetHandle_t _mdns_queue_set = NULL;
static xSemaphoreHandle _mdns_service_semaphore = NULL;
#define MDNS_SERVICE_LOCK() xSemaphoreTake(_mdns_service_semaphore, portMAX_DELAY)
#define MDNS_SERVICE_UNLOCK() xSemaphoreGive(_mdns_service_semaphore)
/*
* MDNS Server Networking
* */
/**
* @brief the receive callback of the raw udp api. Packets are received here
*
*/
static void _mdns_server_recv(void *arg, struct udp_pcb *upcb, struct pbuf *pb, const ip_addr_t *addr, uint16_t port)
{
while(pb != NULL) {
struct pbuf * this_pb = pb;
pb = pb->next;
this_pb->next = NULL;
mdns_server_t * server = (mdns_server_t *)arg;
if (!server || !server->queue || xQueueSend(server->queue, &this_pb, (portTickType)0) != pdPASS) {
pbuf_free(this_pb);
}
}
}
/**
* @brief init the network of MDNS server
*
* @param server The server
*
* @return
* - ESP_OK on success
* - ESP_ERR_INVALID_STATE on igmp/bind error
* - ESP_ERR_NO_MEM on memory error
*/
esp_err_t _mdns_server_init(mdns_server_t * server)
{
esp_err_t err = ESP_OK;
tcpip_adapter_ip_info_t if_ip_info;
err = tcpip_adapter_get_ip_info(server->tcpip_if, &if_ip_info);
if (err) {
return err;
}
ip_addr_t laddr;
IP_ADDR4(&laddr, 224, 0, 0, 251);
ip_addr_t multicast_if_addr = IPADDR4_INIT(if_ip_info.ip.addr);
if (igmp_joingroup((const struct ip4_addr *)&multicast_if_addr.u_addr.ip4, (const struct ip4_addr *)&laddr.u_addr.ip4)) {
return ESP_ERR_INVALID_STATE;
}
struct udp_pcb * pcb = udp_new();
if (!pcb) {
return ESP_ERR_NO_MEM;
}
pcb->remote_port = MDNS_SERVICE_PORT;
if (udp_bind(pcb, &multicast_if_addr, pcb->remote_port) != 0) {
udp_remove(pcb);
return ESP_ERR_INVALID_STATE;
}
pcb->mcast_ttl = 1;
ip_addr_copy(pcb->multicast_ip, multicast_if_addr);
ip_addr_copy(pcb->remote_ip, laddr);
server->pcb = pcb;
udp_recv(pcb, &_mdns_server_recv, server);
return err;
}
/**
* @brief stop the network of MDNS server
*
* @param server The server
*
* @return ESP_OK
*/
esp_err_t _mdns_server_deinit(mdns_server_t * server)
{
if (server->pcb) {
udp_recv(server->pcb, NULL, NULL);
udp_disconnect(server->pcb);
udp_remove(server->pcb);
server->pcb = NULL;
}
return ESP_OK;
}
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#endif
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/**
* @brief send packet over UDP
*
* @param server The server
* @param data byte array containing the packet data
* @param len length of the packet data
*
* @return length of sent packet or 0 on error
*/
static size_t _mdns_server_write(mdns_server_t * server, uint8_t * data, size_t len)
{
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#ifndef MDNS_TEST_MODE
struct pbuf* pbt = pbuf_alloc(PBUF_TRANSPORT, len, PBUF_RAM);
if (pbt == NULL) {
return 0;
}
uint8_t* dst = (uint8_t *)pbt->payload;
memcpy(dst, data, len);
err_t err = udp_sendto(server->pcb, pbt, &(server->pcb->remote_ip), server->pcb->remote_port);
pbuf_free(pbt);
if (err) {
return 0;
}
#endif
return len;
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}
/*
* MDNS Servers
* */
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#ifndef MDNS_TEST_MODE
void mdns_parse_packet(mdns_server_t * server, const uint8_t * data, size_t len);
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/**
* @brief the main MDNS service task. Packets are received and parsed here
*/
static void _mdns_service_task(void *pvParameters)
{
uint8_t i;
struct pbuf * pb;
QueueSetMemberHandle_t queue;
for(;;) {
queue = xQueueSelectFromSet(_mdns_queue_set, portMAX_DELAY);
if (queue && xQueueReceive(queue, &pb, 0) == pdTRUE) {
for(i=0; i<TCPIP_ADAPTER_IF_MAX; i++) {
mdns_server_t * server = _mdns_servers[i];
if (server && server->queue == queue) {
MDNS_MUTEX_LOCK();
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mdns_parse_packet(server, (uint8_t*)pb->payload, pb->len);
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MDNS_MUTEX_UNLOCK();
break;
}
}
pbuf_free(pb);
}
}
}
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#endif
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/**
* @brief get the server assigned to particular interface
*
* @param tcpip_if The interface
*
* @return reference to the server from the server list or NULL if not found
*/
static mdns_server_t * _mdns_server_get(tcpip_adapter_if_t tcpip_if)
{
if (tcpip_if < TCPIP_ADAPTER_IF_MAX) {
return _mdns_servers[tcpip_if];
}
return NULL;
}
/**
* @brief add server to the server list. Start the service thread if not running
*
* @param server The server to add
*
* @return
* - ESP_OK on success
* - ESP_FAIL on error
* - ESP_ERR_* on network error
*/
static esp_err_t _mdns_server_add(mdns_server_t * server)
{
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#ifndef MDNS_TEST_MODE
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if (!_mdns_service_semaphore) {
_mdns_service_semaphore = xSemaphoreCreateMutex();
if (!_mdns_service_semaphore) {
return ESP_FAIL;
}
}
MDNS_SERVICE_LOCK();
if (!_mdns_service_task_handle) {
_mdns_queue_set = xQueueCreateSet(TCPIP_ADAPTER_IF_MAX * MDNS_PACKET_QUEUE_LEN);
if (!_mdns_queue_set) {
MDNS_SERVICE_UNLOCK();
return ESP_FAIL;
}
xTaskCreatePinnedToCore(_mdns_service_task, "mdns", MDNS_SERVICE_STACK_DEPTH, NULL, 1, &_mdns_service_task_handle, 0);
if (!_mdns_service_task_handle) {
vQueueDelete(_mdns_queue_set);
_mdns_queue_set = NULL;
MDNS_SERVICE_UNLOCK();
return ESP_FAIL;
}
}
MDNS_SERVICE_UNLOCK();
if (xQueueAddToSet(server->queue, _mdns_queue_set) != pdPASS) {
return ESP_FAIL;
}
//start UDP
esp_err_t err = _mdns_server_init(server);
if (err) {
return err;
}
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#endif
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_mdns_servers[server->tcpip_if] = server;
return ESP_OK;
}
/**
* @brief remove server from server list. Stop the service thread in no more servers are running
*
* @param server The server to remove
*
* @return
* - ESP_OK on success
* - ESP_FAIL on error
*/
static esp_err_t _mdns_server_remove(mdns_server_t * server)
{
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_mdns_servers[server->tcpip_if] = NULL;
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#ifndef MDNS_TEST_MODE
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//stop UDP
_mdns_server_deinit(server);
if (xQueueRemoveFromSet(server->queue, _mdns_queue_set) != pdPASS) {
return ESP_FAIL;
}
uint8_t i;
for(i=0; i<TCPIP_ADAPTER_IF_MAX; i++) {
if (_mdns_servers[i]) {
break;
}
}
if (i == TCPIP_ADAPTER_IF_MAX) {
//none of the servers are running
MDNS_SERVICE_LOCK();
if (_mdns_service_task_handle) {
vTaskDelete(_mdns_service_task_handle);
vQueueDelete(_mdns_queue_set);
_mdns_queue_set = NULL;
_mdns_service_task_handle = NULL;
}
MDNS_SERVICE_UNLOCK();
}
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#endif
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return ESP_OK;
}
/*
* PARSING
* */
/**
* @brief queues service for answer (if service is already added, append the new answer type)
*
* @param answers Linked list of answers
* @param service Service to add to the answers
* @param type Type of the answer
*
* @return the new linked list of answers
*/
static mdns_answer_item_t * _mdns_add_answer(mdns_answer_item_t * answers, mdns_service_t * service, uint8_t type)
{
//see if we already have the service queued
mdns_answer_item_t * a = answers;
while(a) {
if (a->service == service) {
//just add the new answer type to it
a->answer |= type;
return answers;
}
a = a->next;
}
//prepend the q with this new answer
a = (mdns_answer_item_t *)malloc(sizeof(mdns_answer_item_t));
if (!a) {
return answers;//fail!
}
a->service = service;
a->answer = type;
a->next = answers;
answers = a;
return a;
}
/**
* @brief reads MDNS FQDN into mdns_name_t structure
* FQDN is in format: [hostname.|[instance.]_service._proto.]local.
*
* @param packet MDNS packet
* @param start Starting point of FQDN
* @param name mdns_name_t structure to populate
* @param buf temporary char buffer
*
* @return the address after the parsed FQDN in the packet or NULL on error
*/
static const uint8_t * _mdns_read_fqdn(const uint8_t * packet, const uint8_t * start, mdns_name_t * name, char * buf)
{
size_t index = 0;
while(start[index]) {
if (name->parts == 4) {
return NULL;
}
uint8_t len = start[index++];
if ((len & 0xC0) == 0) {
if (len > 64) {
//length can not be more than 64
return NULL;
}
uint8_t i;
for(i=0; i<len; i++) {
buf[i] = start[index++];
}
buf[len] = '\0';
if (name->parts == 1 && buf[0] != '_'
&& (strcmp(buf, MDNS_DEFAULT_DOMAIN) != 0)
&& (strcmp(buf, "ip6") != 0)
&& (strcmp(buf, "in-addr") != 0)) {
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snprintf((char*)name, MDNS_NAME_BUF_LEN, "%s.%s", name->host, buf);
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} else if (strcmp(buf, MDNS_SUB_STR) == 0) {
name->sub = 1;
} else {
memcpy((uint8_t*)name + (name->parts++ * (MDNS_NAME_BUF_LEN)), buf, len+1);
}
} else {
size_t address = (((uint16_t)len & 0x3F) << 8) | start[index++];
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if ((packet + address) >= start) {
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//reference address can not be after where we are
return NULL;
}
if (_mdns_read_fqdn(packet, packet + address, name, buf)) {
return start + index;
}
return NULL;
}
}
return start + index + 1;
}
/**
* @brief reads and formats MDNS FQDN into mdns_name_t structure
*
* @param packet MDNS packet
* @param start Starting point of FQDN
* @param name mdns_name_t structure to populate
*
* @return the address after the parsed FQDN in the packet or NULL on error
*/
static const uint8_t * _mdns_parse_fqdn(const uint8_t * packet, const uint8_t * start, mdns_name_t * name)
{
name->parts = 0;
name->sub = 0;
name->host[0] = 0;
name->service[0] = 0;
name->proto[0] = 0;
name->domain[0] = 0;
static char buf[MDNS_NAME_BUF_LEN];
const uint8_t * next_data = (uint8_t*)_mdns_read_fqdn(packet, start, name, buf);
if (!next_data || name->parts < 2) {
return 0;
}
if (name->parts == 3) {
memmove((uint8_t*)name + (MDNS_NAME_BUF_LEN), (uint8_t*)name, 3*(MDNS_NAME_BUF_LEN));
name->host[0] = 0;
} else if (name->parts == 2) {
memmove((uint8_t*)(name->domain), (uint8_t*)(name->service), (MDNS_NAME_BUF_LEN));
name->service[0] = 0;
name->proto[0] = 0;
}
if (strcmp(name->domain, MDNS_DEFAULT_DOMAIN) == 0 || strcmp(name->domain, "arpa") == 0) {
return next_data;
}
return 0;
}
/*
* Packet construction
* */
/**
* @brief sets uint16_t value in a packet
*
* @param packet MDNS packet
* @param index offset of uint16_t value
* @param value the value to set
*/
static inline void _mdns_set_u16(uint8_t * packet, uint16_t index, uint16_t value)
{
if ((index + 1) >= MDNS_MAX_PACKET_SIZE) {
return;
}
packet[index] = (value >> 8) & 0xFF;
packet[index+1] = value & 0xFF;
}
/**
* @brief appends byte in a packet, incrementing the index
*
* @param packet MDNS packet
* @param index offset in the packet
* @param value the value to set
*
* @return length of added data: 0 on error or 1 on success
*/
static inline uint8_t _mdns_append_u8(uint8_t * packet, uint16_t * index, uint8_t value)
{
if (*index >= MDNS_MAX_PACKET_SIZE) {
return 0;
}
packet[*index] = value;
*index += 1;
return 1;
}
/**
* @brief appends uint16_t in a packet, incrementing the index
*
* @param packet MDNS packet
* @param index offset in the packet
* @param value the value to set
*
* @return length of added data: 0 on error or 2 on success
*/
static inline uint8_t _mdns_append_u16(uint8_t * packet, uint16_t * index, uint16_t value)
{
if ((*index + 1) >= MDNS_MAX_PACKET_SIZE) {
return 0;
}
_mdns_append_u8(packet, index, (value >> 8) & 0xFF);
_mdns_append_u8(packet, index, value & 0xFF);
return 2;
}
/**
* @brief appends uint32_t in a packet, incrementing the index
*
* @param packet MDNS packet
* @param index offset in the packet
* @param value the value to set
*
* @return length of added data: 0 on error or 4 on success
*/
static inline uint8_t _mdns_append_u32(uint8_t * packet, uint16_t * index, uint32_t value)
{
if ((*index + 3) >= MDNS_MAX_PACKET_SIZE) {
return 0;
}
_mdns_append_u8(packet, index, (value >> 24) & 0xFF);
_mdns_append_u8(packet, index, (value >> 16) & 0xFF);
_mdns_append_u8(packet, index, (value >> 8) & 0xFF);
_mdns_append_u8(packet, index, value & 0xFF);
return 4;
}
/**
* @brief appends answer type, class, ttl and data length to a packet, incrementing the index
*
* @param packet MDNS packet
* @param index offset in the packet
* @param type answer type
* @param ttl answer ttl
*
* @return length of added data: 0 on error or 10 on success
*/
static inline uint8_t _mdns_append_type(uint8_t * packet, uint16_t * index, uint8_t type, uint32_t ttl)
{
if ((*index + 10) >= MDNS_MAX_PACKET_SIZE) {
return 0;
}
if (type == MDNS_ANSWER_PTR) {
_mdns_append_u16(packet, index, MDNS_TYPE_PTR);
_mdns_append_u16(packet, index, MDNS_CLASS_IN);
} else if (type == MDNS_ANSWER_TXT) {
_mdns_append_u16(packet, index, MDNS_TYPE_TXT);
_mdns_append_u16(packet, index, MDNS_CLASS_IN_FLUSH_CACHE);
} else if (type == MDNS_ANSWER_SRV) {
_mdns_append_u16(packet, index, MDNS_TYPE_SRV);
_mdns_append_u16(packet, index, MDNS_CLASS_IN_FLUSH_CACHE);
} else if (type == MDNS_ANSWER_A) {
_mdns_append_u16(packet, index, MDNS_TYPE_A);
_mdns_append_u16(packet, index, MDNS_CLASS_IN_FLUSH_CACHE);
} else if (type == MDNS_ANSWER_AAAA) {
_mdns_append_u16(packet, index, MDNS_TYPE_AAAA);
_mdns_append_u16(packet, index, MDNS_CLASS_IN_FLUSH_CACHE);
} else {
return 0;
}
_mdns_append_u32(packet, index, ttl);
_mdns_append_u16(packet, index, 0);
return 10;
}
/**
* @brief appends single string to a packet, incrementing the index
*
* @param packet MDNS packet
* @param index offset in the packet
* @param string the string to append
*
* @return length of added data: 0 on error or length of the string + 1 on success
*/
static inline uint8_t _mdns_append_string(uint8_t * packet, uint16_t * index, const char * string)
{
uint8_t len = strlen(string);
if ((*index + len + 1) >= MDNS_MAX_PACKET_SIZE) {
return 0;
}
_mdns_append_u8(packet, index, len);
memcpy(packet + *index, string, len);
*index += len;
return len + 1;
}
/**
* @brief appends FQDN to a packet, incrementing the index
*
* @param packet MDNS packet
* @param index offset in the packet
* @param strings string array containing the parts of the FQDN
* @param count number of strings in the array
*
* @return length of added data: 0 on error or length on success
*/
static uint16_t _mdns_append_fqdn(uint8_t * packet, uint16_t * index, const char * strings[], uint8_t count)
{
if (!count) {
return _mdns_append_u8(packet, index, 0);
}
mdns_name_t name;
static char buf[MDNS_NAME_BUF_LEN];
uint8_t len = strlen(strings[0]);
uint8_t * len_location = (uint8_t *)memchr(packet, (char)len, *index);
while(len_location) {
if (memcmp(len_location+1, strings[0], len)) { //not continuing with our string
search_next:
len_location = (uint8_t *)memchr(len_location+1, (char)len, *index - (len_location+1 - packet));
continue;
}
//read string into name and compare
name.parts = 0;
name.sub = 0;
name.host[0] = 0;
name.service[0] = 0;
name.proto[0] = 0;
name.domain[0] = 0;
const uint8_t * content = _mdns_read_fqdn(packet, len_location, &name, buf);
if (!content) {
return 0;
}
if (name.parts == count) {
uint8_t i;
for(i=0; i<count; i++) {
if (strcmp(strings[i], (const char *)&name + (i * (MDNS_NAME_BUF_LEN)))) {
//not our string
goto search_next;
}
}
//we actually have found the string
break;
} else {
goto search_next;
}
}
if (!len_location) {
uint8_t written = _mdns_append_string(packet, index, strings[0]);
if (!written) {
return 0;
}
return written + _mdns_append_fqdn(packet, index, &strings[1], count - 1);
}
uint16_t offset = len_location - packet;
offset |= MDNS_NAME_REF;
return _mdns_append_u16(packet, index, offset);
}
/**
* @brief appends PTR record for service to a packet, incrementing the index
*
* @param packet MDNS packet
* @param index offset in the packet
* @param server the server that is hosting the service
* @param service the service to add record for
*
* @return length of added data: 0 on error or length on success
*/
static uint16_t _mdns_append_ptr_record(uint8_t * packet, uint16_t * index, mdns_server_t * server, mdns_service_t * service)
{
const char * str[4];
uint16_t record_length = 0;
uint8_t part_length;
str[0] = (service->instance)?service->instance
:(server->instance)?server->instance
:server->hostname;
str[1] = service->service;
str[2] = service->proto;
str[3] = MDNS_DEFAULT_DOMAIN;
part_length = _mdns_append_fqdn(packet, index, str + 1, 3);
if (!part_length) {
return 0;
}
record_length += part_length;
part_length = _mdns_append_type(packet, index, MDNS_ANSWER_PTR, MDNS_ANSWER_PTR_TTL);
if (!part_length) {
return 0;
}
record_length += part_length;
uint16_t data_len_location = *index - 2;
part_length = _mdns_append_fqdn(packet, index, str, 4);
if (!part_length) {
return 0;
}
_mdns_set_u16(packet, data_len_location, part_length);
record_length += part_length;
return record_length;
}
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/**
* @brief appends DNS-SD PTR record for service to a packet, incrementing the index
*
* @param packet MDNS packet
* @param index offset in the packet
* @param server the server that is hosting the service
* @param service the service to add record for
*
* @return length of added data: 0 on error or length on success
*/
static uint16_t _mdns_append_sdptr_record(uint8_t * packet, uint16_t * index, mdns_server_t * server, mdns_service_t * service)
{
const char * str[3];
const char * sd_str[4];
uint16_t record_length = 0;
uint8_t part_length;
sd_str[0] = (char*)"_services";
sd_str[1] = (char*)"_dns-sd";
sd_str[2] = (char*)"_udp";
sd_str[3] = MDNS_DEFAULT_DOMAIN;
str[0] = service->service;
str[1] = service->proto;
str[2] = MDNS_DEFAULT_DOMAIN;
part_length = _mdns_append_fqdn(packet, index, sd_str, 4);
record_length += part_length;
part_length = _mdns_append_type(packet, index, MDNS_ANSWER_PTR, MDNS_ANSWER_PTR_TTL);
if (!part_length) {
return 0;
}
record_length += part_length;
uint16_t data_len_location = *index - 2;
part_length = _mdns_append_fqdn(packet, index, str, 3);
if (!part_length) {
return 0;
}
_mdns_set_u16(packet, data_len_location, part_length);
record_length += part_length;
return record_length;
}
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/**
* @brief appends TXT record for service to a packet, incrementing the index
*
* @param packet MDNS packet
* @param index offset in the packet
* @param server the server that is hosting the service
* @param service the service to add record for
*
* @return length of added data: 0 on error or length on success
*/
static uint16_t _mdns_append_txt_record(uint8_t * packet, uint16_t * index, mdns_server_t * server, mdns_service_t * service)
{
const char * str[4];
uint16_t record_length = 0;
uint8_t part_length;
str[0] = (service->instance)?service->instance
:(server->instance)?server->instance
:server->hostname;
str[1] = service->service;
str[2] = service->proto;
str[3] = MDNS_DEFAULT_DOMAIN;
part_length = _mdns_append_fqdn(packet, index, str, 4);
if (!part_length) {
return 0;
}
record_length += part_length;
part_length = _mdns_append_type(packet, index, MDNS_ANSWER_TXT, MDNS_ANSWER_TXT_TTL);
if (!part_length) {
return 0;
}
record_length += part_length;
uint16_t data_len_location = *index - 2;
uint16_t data_len = 0;
if (service->txt_num_items) {
uint8_t len = service->txt_num_items;
const char ** txt = service->txt;
uint8_t i, l;
for(i=0; i<len; i++) {
l = _mdns_append_string(packet, index, txt[i]);
if (!l) {
return 0;
}
data_len += l;
}
}
_mdns_set_u16(packet, data_len_location, data_len);
record_length += data_len;
return record_length;
}
/**
* @brief appends SRV record for service to a packet, incrementing the index
*
* @param packet MDNS packet
* @param index offset in the packet
* @param server the server that is hosting the service
* @param service the service to add record for
*
* @return length of added data: 0 on error or length on success
*/
static uint16_t _mdns_append_srv_record(uint8_t * packet, uint16_t * index, mdns_server_t * server, mdns_service_t * service)
{
const char * str[4];
uint16_t record_length = 0;
uint8_t part_length;
str[0] = (service->instance)?service->instance
:(server->instance)?server->instance
:server->hostname;
str[1] = service->service;
str[2] = service->proto;
str[3] = MDNS_DEFAULT_DOMAIN;
part_length = _mdns_append_fqdn(packet, index, str, 4);
if (!part_length) {
return 0;
}
record_length += part_length;
part_length = _mdns_append_type(packet, index, MDNS_ANSWER_SRV, MDNS_ANSWER_SRV_TTL);
if (!part_length) {
return 0;
}
record_length += part_length;
uint16_t data_len_location = *index - 2;
part_length = 0;
part_length += _mdns_append_u16(packet, index, service->priority);
part_length += _mdns_append_u16(packet, index, service->weight);
part_length += _mdns_append_u16(packet, index, service->port);
if (part_length != 6) {
return 0;
}
str[0] = server->hostname;
str[1] = MDNS_DEFAULT_DOMAIN;
part_length = _mdns_append_fqdn(packet, index, str, 2);
if (!part_length) {
return 0;
}
_mdns_set_u16(packet, data_len_location, part_length + 6);
record_length += part_length + 6;
return record_length;
}
/**
* @brief appends A record to a packet, incrementing the index
*
* @param packet MDNS packet
* @param index offset in the packet
* @param server the server
* @param ip the IP address to add
*
* @return length of added data: 0 on error or length on success
*/
static uint16_t _mdns_append_a_record(uint8_t * packet, uint16_t * index, mdns_server_t * server, uint32_t ip)
{
const char * str[2];
uint16_t record_length = 0;
uint8_t part_length;
str[0] = server->hostname;
str[1] = MDNS_DEFAULT_DOMAIN;
part_length = _mdns_append_fqdn(packet, index, str, 2);
if (!part_length) {
return 0;
}
record_length += part_length;
part_length = _mdns_append_type(packet, index, MDNS_ANSWER_A, MDNS_ANSWER_A_TTL);
if (!part_length) {
return 0;
}
record_length += part_length;
uint16_t data_len_location = *index - 2;
if ((*index + 3) >= MDNS_MAX_PACKET_SIZE) {
return 0;
}
_mdns_append_u8(packet, index, ip & 0xFF);
_mdns_append_u8(packet, index, (ip >> 8) & 0xFF);
_mdns_append_u8(packet, index, (ip >> 16) & 0xFF);
_mdns_append_u8(packet, index, (ip >> 24) & 0xFF);
_mdns_set_u16(packet, data_len_location, 4);
record_length += 4;
return record_length;
}
/**
* @brief appends AAAA record to a packet, incrementing the index
*
* @param packet MDNS packet
* @param index offset in the packet
* @param server the server
* @param ipv6 the IPv6 address to add
*
* @return length of added data: 0 on error or length on success
*/
static uint16_t _mdns_append_aaaa_record(uint8_t * packet, uint16_t * index, mdns_server_t * server, uint8_t * ipv6)
{
const char * str[2];
uint16_t record_length = 0;
uint8_t part_length;
str[0] = server->hostname;
str[1] = MDNS_DEFAULT_DOMAIN;
part_length = _mdns_append_fqdn(packet, index, str, 2);
if (!part_length) {
return 0;
}
record_length += part_length;
part_length = _mdns_append_type(packet, index, MDNS_ANSWER_AAAA, MDNS_ANSWER_AAAA_TTL);
if (!part_length) {
return 0;
}
record_length += part_length;
uint16_t data_len_location = *index - 2;
if ((*index + 15) >= MDNS_MAX_PACKET_SIZE) {
return 0;
}
part_length = sizeof(ip6_addr_t);
memcpy(packet + *index, ipv6, part_length);
*index += part_length;
_mdns_set_u16(packet, data_len_location, part_length);
record_length += part_length;
return record_length;
}
/**
* @brief sends all collected answers
*
* @param server the server
* @param answers linked list of answers
*/
static void _mdns_send_answers(mdns_server_t * server, mdns_answer_item_t * answers)
{
bool send_ip = false;
static uint8_t packet[MDNS_MAX_PACKET_SIZE];
uint16_t index = MDNS_HEAD_LEN;
uint8_t answer_count = 0;
memset(packet, 0, MDNS_HEAD_LEN);
_mdns_set_u16(packet, MDNS_HEAD_FLAGS_OFFSET, MDNS_FLAGS_AUTHORITATIVE);
while(answers) {
if (answers->answer & MDNS_ANSWER_A) {
answers->answer &= ~MDNS_ANSWER_A;
send_ip = true;
}
if (answers->service) {
if (answers->answer & MDNS_ANSWER_PTR) {
if (!_mdns_append_ptr_record(packet, &index, server, answers->service)) {
return;
}
answer_count += 1;
}
if (answers->answer & MDNS_ANSWER_TXT) {
if (!_mdns_append_txt_record(packet, &index, server, answers->service)) {
return;
}
answer_count += 1;
}
if (answers->answer & MDNS_ANSWER_SRV) {
if (!_mdns_append_srv_record(packet, &index, server, answers->service)) {
return;
}
answer_count += 1;
}
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if (answers->answer & MDNS_ANSWER_SDPTR) {
if (!_mdns_append_sdptr_record(packet, &index, server, answers->service)) {
return;
}
answer_count += 1;
}
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}
mdns_answer_item_t * a = answers;
answers = answers->next;
free(a);
}
if (send_ip) {
tcpip_adapter_ip_info_t if_ip_info;
tcpip_adapter_get_ip_info(server->tcpip_if, &if_ip_info);
if (!_mdns_append_a_record(packet, &index, server, if_ip_info.ip.addr)) {
return;
}
answer_count += 1;
//add ipv6 if available
struct ip6_addr if_ip6;
if (!tcpip_adapter_get_ip6_linklocal(server->tcpip_if, &if_ip6)) {
uint8_t * v6addr = (uint8_t*)if_ip6.addr;
//check if not 0
int i;
for(i=0;i<sizeof(ip6_addr_t);i++) {
if (v6addr[i]) {
break;
}
}
if (i<sizeof(ip6_addr_t)) {
if (!_mdns_append_aaaa_record(packet, &index, server, v6addr)) {
return;
}
answer_count += 1;
}
}
}
_mdns_set_u16(packet, MDNS_HEAD_ANSWERS_OFFSET, answer_count);
_mdns_server_write(server, packet, index);
}
/**
* @brief appends search result from query
*
* @param server the server
* @param r the temporary result to copy
*/
static void _mdns_add_result(mdns_server_t * server, mdns_result_temp_t * r)
{
mdns_result_t * n = (mdns_result_t *)malloc(sizeof(mdns_result_t));
if (!n) {
return;
}
n->priority = r->priority;
n->weight = r->weight;
n->port = r->port;
n->addr.addr = r->addr;
size_t hlen = strlen(r->host);
if (hlen) {
n->host = strdup(r->host);
if (!n->host) {
free(n);
return;
}
} else {
n->host = NULL;
}
size_t ilen = strlen(r->instance);
if (ilen) {
n->instance = strdup(r->instance);
if (!n->instance) {
free((char *)n->host);
free(n);
return;
}
} else {
n->instance = NULL;
}
size_t tlen = strlen(r->txt);
if (tlen) {
n->txt = strdup(r->txt);
if (!n->txt) {
free((char *)n->host);
free((char *)n->instance);
free(n);
return;
}
} else {
n->txt = NULL;
}
memcpy((uint8_t *)n->addrv6.addr, r->addrv6, sizeof(ip6_addr_t));
mdns_result_t * o = server->search.results;
server->search.results = n;
n->next = o;
}
/**
* @brief finds service from given service type
* @param server the server
* @param service service type to match
* @param proto proto to match
*
* @return the service item if found or NULL on error
*/
static mdns_srv_item_t * _mdns_get_service_item(mdns_server_t * server, const char * service, const char * proto)
{
mdns_srv_item_t * s = server->services;
while(s) {
if (!strcmp(s->service->service, service) && !strcmp(s->service->proto, proto)) {
return s;
}
s = s->next;
}
return NULL;
}
/**
* @brief creates/allocates new service
* @param service service type
* @param proto service proto
* @param port service port
*
* @return pointer to the service or NULL on error
*/
static mdns_service_t * _mdns_create_service(const char * service, const char * proto, uint16_t port)
{
mdns_service_t * s = (mdns_service_t *)malloc(sizeof(mdns_service_t));
if (!s) {
return NULL;
}
s->priority = 0;
s->weight = 0;
s->txt_num_items = 0;
s->instance = NULL;
s->txt = NULL;
s->port = port;
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s->service = strndup(service, MDNS_NAME_BUF_LEN - 1);
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if (!s->service) {
free(s);
return NULL;
}
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s->proto = strndup(proto, MDNS_NAME_BUF_LEN - 1);
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if (!s->proto) {
free((char *)s->service);
free(s);
return NULL;
}
return s;
}
/**
* @brief free service memory
*
* @param service the service
*/
static void _mdns_free_service(mdns_service_t * service)
{
if (!service) {
return;
}
free((char *)service->instance);
free((char *)service->service);
free((char *)service->proto);
if (service->txt_num_items) {
uint8_t i;
for(i=0; i<service->txt_num_items; i++) {
free((char *)service->txt[i]);
}
}
free(service->txt);
free(service);
}
/**
* @brief read uint16_t from a packet
* @param packet the packet
* @param index index in the packet where the value starts
*
* @return the value
*/
static inline uint16_t _mdns_read_u16(const uint8_t * packet, uint16_t index)
{
return (uint16_t)(packet[index]) << 8 | packet[index+1];
}
/**
* @brief main packet parser
*
* @param server the server
* @param data byte array holding the packet data
* @param len length of the byte array
*/
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void mdns_parse_packet(mdns_server_t * server, const uint8_t * data, size_t len)
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{
static mdns_name_t n;
static mdns_result_temp_t a;
const uint8_t * content = data + MDNS_HEAD_LEN;
mdns_name_t * name = &n;
memset(name, 0, sizeof(mdns_name_t));
uint16_t questions = _mdns_read_u16(data, MDNS_HEAD_QUESTIONS_OFFSET);
uint16_t answers = _mdns_read_u16(data, MDNS_HEAD_ANSWERS_OFFSET);
uint16_t additional = _mdns_read_u16(data, MDNS_HEAD_ADDITIONAL_OFFSET);
if (questions) {
uint8_t qs = questions;
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mdns_answer_item_t * answer_items = NULL;
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while(qs--) {
content = _mdns_parse_fqdn(data, content, name);
if (!content) {
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answers = 0;
additional = 0;
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break;//error
}
uint16_t type = _mdns_read_u16(content, MDNS_TYPE_OFFSET);
content = content + 4;
if (!name->service[0] || !name->proto[0]) {
if (type == MDNS_TYPE_A || type == MDNS_TYPE_AAAA || type == MDNS_TYPE_ANY) {//send A + AAAA
if (name->host[0] && server->hostname && server->hostname[0] && !strcmp(name->host, server->hostname)) {
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answer_items = _mdns_add_answer(answer_items, NULL, MDNS_ANSWER_A);
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}
}
continue;
}
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//is this a dns-sd service discovery meta query?
if (!strcmp(name->host, "_services") && !strcmp(name->service, "_dns-sd") && !strcmp(name->proto, "_udp") && !strcmp(name->domain, MDNS_DEFAULT_DOMAIN) && type == MDNS_TYPE_PTR)
{
//add answers for all services
mdns_srv_item_t * s = server->services;
while(s) {
if (s->service->service && s->service->proto) {
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answer_items = _mdns_add_answer(answer_items, s->service, MDNS_ANSWER_SDPTR);
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}
s = s->next;
}
continue;
}
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if (name->sub) {
continue;
}
mdns_srv_item_t * si = _mdns_get_service_item(server, name->service, name->proto);
if (!si) {
//service not found
continue;
}
if (type == MDNS_TYPE_PTR) {
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answer_items = _mdns_add_answer(answer_items, si->service, MDNS_ANSWER_ALL);
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} else if (type == MDNS_TYPE_TXT) {
//match instance/host
const char * host = (si->service->instance)?si->service->instance
:(server->instance)?server->instance
:server->hostname;
if (!host || !host[0] || !name->host[0] || strcmp(name->host, host)) {
continue;
}
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answer_items = _mdns_add_answer(answer_items, si->service, MDNS_ANSWER_TXT);
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} else if (type == MDNS_TYPE_SRV) {
//match instance/host
const char * host = (si->service->instance)?si->service->instance
:(server->instance)?server->instance
:server->hostname;
if (!host || !host[0] || !name->host[0] || strcmp(name->host, host)) {
continue;
}
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answer_items = _mdns_add_answer(answer_items, si->service, MDNS_ANSWER_SRV | MDNS_ANSWER_A);
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} else if (type == MDNS_TYPE_ANY) {//send all
//match host
if (!name->host[0] || !server->hostname || !server->hostname[0] || strcmp(name->host, server->hostname)) {
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answer_items = _mdns_add_answer(answer_items, si->service, MDNS_ANSWER_ALL);
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}
}
}
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if (answer_items) {
_mdns_send_answers(server, answer_items);
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}
}
if (server->search.running && (answers || additional)) {
mdns_result_temp_t * answer = &a;
memset(answer, 0, sizeof(mdns_result_temp_t));
while(content < (data + len)) {
content = _mdns_parse_fqdn(data, content, name);
if (!content) {
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return;//error
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}
uint16_t type = _mdns_read_u16(content, MDNS_TYPE_OFFSET);
uint16_t data_len = _mdns_read_u16(content, MDNS_LEN_OFFSET);
const uint8_t * data_ptr = content + MDNS_DATA_OFFSET;
content = data_ptr + data_len;
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if(content > (data + len)){
return;
}
Initial mDNS component and example
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if (type == MDNS_TYPE_PTR) {
if (!_mdns_parse_fqdn(data, data_ptr, name)) {
continue;//error
}
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#ifndef MDNS_TEST_MODE
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if (server->search.host[0] ||
(strcmp(name->service, server->search.service) != 0) ||
(strcmp(name->proto, server->search.proto) != 0)) {
continue;//not searching for service or wrong service/proto
}
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#endif
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strlcpy(answer->instance, name->host, MDNS_NAME_BUF_LEN);
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} else if (type == MDNS_TYPE_SRV) {
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#ifndef MDNS_TEST_MODE
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if (server->search.host[0] ||
(strcmp(name->service, server->search.service) != 0) ||
(strcmp(name->proto, server->search.proto) != 0)) {
continue;//not searching for service or wrong service/proto
}
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#endif
Initial mDNS component and example
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if (answer->instance[0]) {
if (strcmp(answer->instance, name->host) != 0) {
continue;//instance name is not the same as the one in the PTR record
}
} else {
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strlcpy(answer->instance, name->host, MDNS_NAME_BUF_LEN);
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}
//parse record value
if (!_mdns_parse_fqdn(data, data_ptr + MDNS_SRV_FQDN_OFFSET, name)) {
continue;//error
}
answer->ptr = 1;
answer->priority = _mdns_read_u16(data_ptr, MDNS_SRV_PRIORITY_OFFSET);
answer->weight = _mdns_read_u16(data_ptr, MDNS_SRV_WEIGHT_OFFSET);
answer->port = _mdns_read_u16(data_ptr, MDNS_SRV_PORT_OFFSET);
if (answer->host[0]) {
if (strcmp(answer->host, name->host) != 0) {
answer->addr = 0;
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strlcpy(answer->host, name->host, MDNS_NAME_BUF_LEN);
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}
} else {
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strlcpy(answer->host, name->host, MDNS_NAME_BUF_LEN);
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}
} else if (type == MDNS_TYPE_TXT) {
uint16_t i=0,b=0, y;
while(i < data_len) {
uint8_t partLen = data_ptr[i++];
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if((i+partLen) > data_len){
break;//error
}
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//check if partLen will fit in the buffer
if (partLen > (MDNS_TXT_MAX_LEN - b - 1)) {
break;
}
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for(y=0; y<partLen; y++) {
char d = data_ptr[i++];
answer->txt[b++] = d;
}
if (i<data_len) {
answer->txt[b++] = '&';
}
}
answer->txt[b] = 0;
} else if (type == MDNS_TYPE_AAAA) {
if (server->search.host[0]) {
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#ifndef MDNS_TEST_MODE
Initial mDNS component and example
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if (strcmp(name->host, server->search.host) != 0) {
continue;//wrong host
}
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#endif
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} else if (!answer->ptr) {
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strlcpy(answer->host, name->host, MDNS_NAME_BUF_LEN);
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} else if (strcmp(answer->host, name->host) != 0) {
continue;//wrong host
}
memcpy(answer->addrv6, data_ptr, sizeof(ip6_addr_t));
} else if (type == MDNS_TYPE_A) {
if (server->search.host[0]) {
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#ifndef MDNS_TEST_MODE
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if (strcmp(name->host, server->search.host) != 0) {
continue;//wrong host
}
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#endif
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} else if (!answer->ptr) {
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strlcpy(answer->host, name->host, MDNS_NAME_BUF_LEN);
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} else if (strcmp(answer->host, name->host) != 0) {
continue;//wrong host
}
if (server->search.running && answer->addr) {
_mdns_add_result(server, answer);//another IP for our host
}
IP4_ADDR(answer, data_ptr[0], data_ptr[1], data_ptr[2], data_ptr[3]);
}
}
if (server->search.running && (server->search.host[0] || answer->ptr) && answer->addr) {
_mdns_add_result(server, answer);
}
//end while
}
}
/*
* Public Methods
* */
esp_err_t mdns_init(tcpip_adapter_if_t tcpip_if, mdns_server_t ** mdns_server)
{
esp_err_t err = ESP_OK;
if (tcpip_if >= TCPIP_ADAPTER_IF_MAX) {
return ESP_ERR_INVALID_ARG;
}
if (_mdns_server_get(tcpip_if)) {
return ESP_ERR_INVALID_STATE;
}
uint8_t mode;
err = esp_wifi_get_mode((wifi_mode_t*)&mode);
if (err) {
return err;
}
if ((tcpip_if == TCPIP_ADAPTER_IF_STA && !(mode & WIFI_MODE_STA))
|| (tcpip_if == TCPIP_ADAPTER_IF_AP && !(mode & WIFI_MODE_AP))) {
return ESP_ERR_INVALID_ARG;
}
mdns_server_t * server = (mdns_server_t *)malloc(sizeof(mdns_server_t));
if (!server) {
return ESP_ERR_NO_MEM;
}
server->tcpip_if = tcpip_if;
server->hostname = NULL;
server->instance = NULL;
server->services = NULL;
server->search.host[0] = 0;
server->search.service[0] = 0;
server->search.proto[0] = 0;
server->search.running = false;
server->search.results = NULL;
server->pcb = NULL;
server->lock = xSemaphoreCreateMutex();
if (!server->lock) {
free(server);
return ESP_ERR_NO_MEM;
}
server->search.lock = xSemaphoreCreateMutex();
if (!server->search.lock) {
vSemaphoreDelete(server->lock);
free(server);
return ESP_ERR_NO_MEM;
}
server->queue = xQueueCreate(MDNS_PACKET_QUEUE_LEN, sizeof(struct pbuf *));
if (!server->queue) {
vSemaphoreDelete(server->lock);
vSemaphoreDelete(server->search.lock);
free(server);
return ESP_ERR_NO_MEM;
}
if (_mdns_server_add(server)) {
//service start failed!
vSemaphoreDelete(server->lock);
vSemaphoreDelete(server->search.lock);
vQueueDelete(server->queue);
free(server);
return ESP_FAIL;
}
const char * hostname = NULL;
tcpip_adapter_get_hostname(server->tcpip_if, &hostname);
mdns_set_hostname(server, hostname);
*mdns_server = server;
return ESP_OK;
}
void mdns_free(mdns_server_t * server)
{
if (!server) {
return;
}
_mdns_server_remove(server);
mdns_service_remove_all(server);
MDNS_MUTEX_LOCK();
free((char*)server->hostname);
free((char*)server->instance);
if (server->queue) {
struct pbuf * c;
while(xQueueReceive(server->queue, &c, 0) == pdTRUE) {
pbuf_free(c);
}
vQueueDelete(server->queue);
}
if (server->search.running) {
mdns_query_end(server);
}
mdns_result_free(server);
vSemaphoreDelete(server->search.lock);
MDNS_MUTEX_UNLOCK();
vSemaphoreDelete(server->lock);
free(server);
}
esp_err_t mdns_set_hostname(mdns_server_t * server, const char * hostname)
{
if (!server) {
return ESP_ERR_INVALID_ARG;
}
address security issues with mDNS
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if (strlen(hostname) > (MDNS_NAME_BUF_LEN - 1)) {
return ESP_ERR_INVALID_ARG;
}
Initial mDNS component and example
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MDNS_MUTEX_LOCK();
free((char*)server->hostname);
implement fixes for issues found while fuzz testing
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server->hostname = strndup(hostname, MDNS_NAME_BUF_LEN - 1);
Initial mDNS component and example
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if (!server->hostname) {
MDNS_MUTEX_UNLOCK();
return ESP_ERR_NO_MEM;
}
MDNS_MUTEX_UNLOCK();
return ERR_OK;
}
esp_err_t mdns_set_instance(mdns_server_t * server, const char * instance)
{
if (!server) {
return ESP_ERR_INVALID_ARG;
}
address security issues with mDNS
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if (strlen(instance) > (MDNS_NAME_BUF_LEN - 1)) {
return ESP_ERR_INVALID_ARG;
}
Initial mDNS component and example
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MDNS_MUTEX_LOCK();
free((char*)server->instance);
implement fixes for issues found while fuzz testing
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server->instance = strndup(instance, MDNS_NAME_BUF_LEN - 1);
Initial mDNS component and example
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if (!server->instance) {
MDNS_MUTEX_UNLOCK();
return ESP_ERR_NO_MEM;
}
MDNS_MUTEX_UNLOCK();
return ERR_OK;
}
/*
* MDNS SERVICES
* */
esp_err_t mdns_service_add(mdns_server_t * server, const char * service, const char * proto, uint16_t port)
{
if (!server || !service || !proto || !port) {
//bad argument
return ESP_ERR_INVALID_ARG;
}
mdns_srv_item_t * item = _mdns_get_service_item(server, service, proto);
if (item) {
//we already have that service
return mdns_service_port_set(server, service, proto, port);
}
mdns_service_t * s = _mdns_create_service(service, proto, port);
if (!s) {
return ESP_ERR_NO_MEM;
}
item = (mdns_srv_item_t *)malloc(sizeof(mdns_srv_item_t));
if (!item) {
return ESP_ERR_NO_MEM;
}
item->service = s;
item->next = server->services;
server->services = item;
return ESP_OK;
}
esp_err_t mdns_service_port_set(mdns_server_t * server, const char * service, const char * proto, uint16_t port)
{
if (!server || !server->services || !service || !proto || !port) {
return ESP_ERR_INVALID_ARG;
}
mdns_srv_item_t * s = _mdns_get_service_item(server, service, proto);
if (!s) {
return ESP_ERR_NOT_FOUND;
}
MDNS_MUTEX_LOCK();
s->service->port = port;
MDNS_MUTEX_UNLOCK();
return ESP_OK;
}
esp_err_t mdns_service_txt_set(mdns_server_t * server, const char * service, const char * proto, uint8_t num_items, const char ** txt)
{
if (!server || !server->services || !service || !proto) {
return ESP_ERR_INVALID_ARG;
}
mdns_srv_item_t * s = _mdns_get_service_item(server, service, proto);
if (!s) {
return ESP_ERR_NOT_FOUND;
}
MDNS_MUTEX_LOCK();
if (s->service->txt_num_items) {
uint8_t i;
for(i=0; i<s->service->txt_num_items; i++) {
free((char *)s->service->txt[i]);
}
}
free(s->service->txt);
if (num_items) {
s->service->txt = (const char **)malloc(sizeof(char *) * num_items);
if (!s->service->txt) {
s->service->txt_num_items = 0;
goto fail;
}
uint8_t i;
s->service->txt_num_items = num_items;
for(i=0; i<num_items; i++) {
s->service->txt[i] = strdup(txt[i]);
if (!s->service->txt[i]) {
s->service->txt_num_items = i;
goto fail;
}
}
}
MDNS_MUTEX_UNLOCK();
return ESP_OK;
fail:
MDNS_MUTEX_UNLOCK();
return ESP_ERR_NO_MEM;
}
esp_err_t mdns_service_instance_set(mdns_server_t * server, const char * service, const char * proto, const char * instance)
{
if (!server || !server->services || !service || !proto) {
return ESP_ERR_INVALID_ARG;
}
address security issues with mDNS
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if (strlen(instance) > (MDNS_NAME_BUF_LEN - 1)) {
return ESP_ERR_INVALID_ARG;
}
Initial mDNS component and example
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mdns_srv_item_t * s = _mdns_get_service_item(server, service, proto);
if (!s) {
return ESP_ERR_NOT_FOUND;
}
MDNS_MUTEX_LOCK();
free((char*)s->service->instance);
s->service->instance = strdup(instance);
if (!s->service->instance) {
MDNS_MUTEX_UNLOCK();
return ESP_ERR_NO_MEM;
}
MDNS_MUTEX_UNLOCK();
return ESP_OK;
}
esp_err_t mdns_service_remove(mdns_server_t * server, const char * service, const char * proto)
{
if (!server || !server->services || !service || !proto) {
return ESP_ERR_INVALID_ARG;
}
mdns_srv_item_t * s = _mdns_get_service_item(server, service, proto);
if (!s) {
return ESP_ERR_NOT_FOUND;
}
//first item
if (server->services == s) {
MDNS_MUTEX_LOCK();
server->services = server->services->next;
MDNS_MUTEX_UNLOCK();
_mdns_free_service(s->service);
free(s);
return ESP_OK;
}
//not first item
mdns_srv_item_t * a = server->services;
while(a->next && a->next != s) {
a = a->next;
}
//next item of the current item is our item
if (a->next == s) {
MDNS_MUTEX_LOCK();
a->next = s->next;
MDNS_MUTEX_UNLOCK();
_mdns_free_service(s->service);
free(s);
return ESP_OK;
}
//how did we end here?
return ESP_FAIL;
}
esp_err_t mdns_service_remove_all(mdns_server_t * server)
{
if (!server) {
return ESP_ERR_INVALID_ARG;
}
if (!server->services) {
return ESP_OK;
}
MDNS_MUTEX_LOCK();
mdns_srv_item_t * a = server->services;
server->services = NULL;
while(a) {
mdns_srv_item_t * s = a;
a = a->next;
_mdns_free_service(s->service);
free(s);
}
MDNS_MUTEX_UNLOCK();
return ESP_OK;
}
/*
* MDNS QUERY
* */
implement fixes for issues found while fuzz testing
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size_t mdns_query(mdns_server_t * server, const char * service, const char * proto, uint32_t timeout)
Initial mDNS component and example
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{
if (!server || !service) {
return 0;
}
MDNS_SEARCH_LOCK();
uint16_t qtype = MDNS_TYPE_PTR;
mdns_result_free(server);
if (proto) {
server->search.host[0] = 0;
address security issues with mDNS
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strlcpy(server->search.service, service, MDNS_NAME_BUF_LEN);
strlcpy(server->search.proto, proto, MDNS_NAME_BUF_LEN);
Initial mDNS component and example
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} else {
address security issues with mDNS
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strlcpy(server->search.host, service, MDNS_NAME_BUF_LEN);
Initial mDNS component and example
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server->search.service[0] = 0;
server->search.proto[0] = 0;
qtype = MDNS_TYPE_A;
}
uint8_t hostname_len = strlen(server->search.host);
uint8_t service_type_len = strlen(server->search.service);
uint8_t protoname_len = strlen(server->search.proto);
size_t len = 23; //head+type+class+(strlen(local)+1)+fqdn_end
if (hostname_len) {
len += hostname_len + 1;
} else if (service_type_len) {
len += service_type_len + protoname_len + 2;
}
uint8_t * packet = (uint8_t *)malloc(len);
if (!packet) {
return 0;
}
memset(packet, 0, len);
_mdns_set_u16(packet, MDNS_HEAD_QUESTIONS_OFFSET, 1);
uint16_t index = MDNS_HEAD_LEN;
if (hostname_len) {
_mdns_append_string(packet, &index, server->search.host);
} else if (service_type_len) {
_mdns_append_string(packet, &index, server->search.service);
_mdns_append_string(packet, &index, server->search.proto);
}
_mdns_append_string(packet, &index, MDNS_DEFAULT_DOMAIN);
_mdns_append_u8(packet, &index, 0); //fqdn_end
_mdns_append_u16(packet, &index, qtype);
_mdns_append_u16(packet, &index, MDNS_CLASS_IN);
MDNS_MUTEX_LOCK();
size_t written = _mdns_server_write(server, packet, index);
MDNS_MUTEX_UNLOCK();
free(packet);
if (written != index) {
return 0;
}
server->search.running = true;
if (timeout) {
uint32_t startAt = xTaskGetTickCount() * portTICK_PERIOD_MS;
while(server->search.running && ((xTaskGetTickCount() * portTICK_PERIOD_MS) - startAt) < timeout) {
vTaskDelay(1 / portTICK_PERIOD_MS);
}
server->search.running = false;
MDNS_SEARCH_UNLOCK();
return mdns_result_get_count(server);
}
return 0;
}
size_t mdns_query_end(mdns_server_t * server)
{
if (!server || !server->search.running) {
return 0;
}
server->search.running = false;
MDNS_SEARCH_UNLOCK();
return mdns_result_get_count(server);
}
esp_err_t mdns_result_free(mdns_server_t * server)
{
if (!server || server->search.running || !server->search.results) {
return ESP_ERR_INVALID_ARG;
}
while(server->search.results) {
const mdns_result_t * r = server->search.results;
server->search.results = (mdns_result_t *)r->next;
free((char *)r->host);
free((char *)r->instance);
free((char *)r->txt);
free((mdns_result_t *)r);
}
server->search.results = NULL;
return ESP_OK;
}
size_t mdns_result_get_count(mdns_server_t * server)
{
if (!server || !server->search.results) {
return 0;
}
size_t len = 0;
const mdns_result_t * r = server->search.results;
while(r) {
len++;
r = r->next;
}
return len;
}
const mdns_result_t * mdns_result_get(mdns_server_t * server, size_t num)
{
if (!server || !server->search.results) {
return NULL;
}
size_t len = 0;
const mdns_result_t * r = server->search.results;
while(r) {
if (len++ == num) {
return r;
}
r = r->next;
}
return NULL;
}
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